Place the potatoes in a pot and cover them with about an inch of cold water. Bring the water to a boil and reduce the heat, simmering for 10 minutes. While the potatoes are simmering, combine the other ingredients and set aside. After 10 minutes, stick a paring knife into a potato – if it goes in without resistance, they’re ready. If they’re not ready, keep checking them every minute. Once they’re ready, drain them in a colander.
Holding them with tongs, cut each potato in half and place in a large bowl. Cutting them in half lets the butter penetrate the potatoes better. Once you’ve cut all the potatoes, pour the rest of the ingredients into the bowl and toss until coated. Serve immediately.